Gestational diabetes mellitus (GDM) is a type of diabetes that can develop during pregnancy in women who don’t already have diabetes. It is defined as any degree of glucose intolerance with onset or first recognition during pregnancy. GDM can be classified as A1GDM and A2GDM. The classification of gestational diabetes managed without medication and responsive to nutritional therapy is as diet-controlled gestational diabetes (GDM) or A1GDM. Conversely, gestational diabetes managed with medication to achieve adequate glycemic control classifies as A2GDM.

The placenta produces hormones that can make it difficult for the body to use insulin effectively, leading to high blood sugar levels. Although any woman can develop GDM during pregnancy, some of the factors that may increase the risk include being overweight or obese, having a family history of diabetes, having given birth previously to an infant weighing greater than 9 pounds, being older than 25, and being African-American, American Indian, Asian American, Hispanic or Latino, or Pacific Islander.

GDM can be diagnosed through laboratory screening methods at 24 to 28 weeks of pregnancy. The American Diabetes Association recommends screening for undiagnosed type 2 diabetes at the first prenatal visit in women with diabetes risk factors. In pregnant women not known to have diabetes, GDM testing should be performed at 24 to 28 weeks of gestation.

The treatment for GDM includes monitoring blood sugar levels, following a healthy eating plan, and getting regular physical activity. The amount of exercise recommended in GDM is 30 minutes of moderate-intensity aerobic exercise at least five days a week or a minimum of 150 minutes per week. Women with diagnosed GDM should be screened for persistent diabetes 6 to 12 weeks postpartum, and it is recommended that women with a history of GDM undergo lifelong screening for the development of diabetes or prediabetes at least every three years.